Sulphines and Sulphenes

Di-t-butylsulphine has been suggested to undergo a one-electron transfer from t-butylmagnesium chloride to give eventually t-butyl alcohol and di-t-butyl 

van der Leij and B. Zwanenburg, Reel. Trav. Chim. Pays-Bas, 1980,99,49. 

Co-ordination compounds of platinum that involve sulphines as ligands have been prepared. Geometrical isomers of thione S-imides (11), which are the nitrogen analogues of sulphines, have been reported, and thiosulphines, R R C=S=S, have been postulated as new reactive intermediates.  

Syntheses of [ rf-CsHs)WiC0)3S02CH2D and l(Ph3P)Mn(CO)4S02CH3] that involve the insertion of sulphene into the metal-deuterium and the metal-hydrogen bond have been reported. 

PART III Thioureas, Thiosemicarbazides, Thioamides, Thiono- and Dithio-carboxylic Acids, and their Selenium Analogues byJ. K. Landquist 

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Thio- and Seleno-carbonyl Compounds Sulphines and sulphenes... 

Change of personnel has led to the division of the wide-ranging chapters on thiocarbonyl compounds and on ylides into more manageable parts. In keeping with more recent work, the short sections on sulphines and sulphenes have been confined to the chapter on thiocarbonyl compounds. To avoid possible inconsistencies, the chemistry of sulphonyl, sulphinyl, and sulphenyl carbanions has been largely included in the chapter on ylides. The order of the chapters has been revised so that the chemistry of acyclic sulphur compounds and sulphur-containing functional groups is covered before cyclic systems. 

Radicals can affect thiol groups in proteins and peptides in a number of different ways. The response might be formation or loss of disulphide bridges. More dramatic free radical exposure can lead to the formation of sulphenic, sulphinic and sulphonic acids. The loss of free thiol groups can be assessed utilizing the methods described here. 

Although the fragmentation reactions of the molecular ions of sul-phones and sulphoxides varied, the first step in rationalizing their behaviour was initial isomerization to sulphinate (64) and sulphenate esters (65). A variety of reactions of this type has been collated by Fields and Meyerson (1968), who pointed out that isomerization of sulphoxides to sulphenate esters was a known thermal reaction (see also, Kutz and Weininger, 1968, Kinstle et al., 1968b). In experiments designed to compare the mass-spectral and thermal behaviour of a series of sulphoxides, it was observed that the thermal isomerization appeared to proceed, but no comparable behaviour was observed in the mass spectra (Entwistle et al., 1967). 

Other reagents which react with arsonium ylides are phenyl sulphine and phenyl sulphene (equation 19). Ethyl cinnamate is also a product of the latter reaction. 

For individuals interested in the energetics of sulphinic acids and their derivatives, we refer the reader to B. Bujnicki, M. Miko lajczyk and J. Omenlanczuk, Thermochemistry and thermolysis of sulphinic acid derivatives , in The Chemistry of Sulphinic Acids, Esters and their Derivatives (Ed. S. Patai), Wiley, Chichester, 1989. The comprehensive comparison of the interplay of structure and energetics of sulphinic and sulphonic acid (and, oh yes, sulphenic acid) derivatives is still unwritten and no doubt awaits a chapter in a yet-to-be-organized Supplement volume. 

PhS(0)(0Ph)Me + RLi and LiX - PhSOCH X + PhSO Me]/ or reduction with homologation (with RjCuLi and LiX)/ Standard sulphinylation procedures reported include electrophilic substitution of phenols with ArSOCl and AlClj and the preparation of optically active sulphoxides from resolved (—)-menthyl sulphinates with ( )-l-alkenylmagnesium bromides or arylthiomethyl- or arylsulphonylmethyl-lithium compounds/ A practical route to 1-alkenyl sulphoxides uses non-activated alkynes and sulphenic acids, generated in situ from the thermolysis of 2-cyanoethyl phenyl sulphoxides/ ... 

In a set of volumes on sulphur-containing functional groups, the volume on the sulphonium group appeared in 1981 (in two parts). The present volume deals with sulphones and sulphoxides and further volumes, one on derivatives of sulphinic acids and another on derivatives of sulphenic acids, are now in the course of preparation, with a volume on sulphonic acid derivatives planned for the more distant future. 

The Chemistry of Sulphinic Acids, Esters and Derivatives The Chemistry of Sulphenic Acids, Esters and Derivatives... 

The chemistry of sulphinic acids, esters and their derivatives The chemistry of sulphenic acids and their derivatives The chemistry of enols... 

Tropothione 2 can be oxidized with an equimolar amount of m-chloroper-benzoic acid. Below 213 K, a sulphinic species, tropothione-S-oxide 3, has been isolated.42 In turn, S-oxide 3 with CF3COOH forms a sulphenic acid 4, which is quite stable at room temperature. Compounds 3 and 4 have been characterized with the aid of 33S NMR spectroscopy. The 33S chemical shift is -6 ppm for 3 and —85 ppm for 4. In agreement with findings for sulphides and sulphoxides, the bonding of an oxygen atom to sulphur in tropothione induces a downfield shift of the 33S resonance. 

One special case is that of the reactive intermediates, the sulphenes (252), and the isolable compounds, the sulphines (253). In the first place, cycloadditions of these species... 

Calculations227 indicate thatthese intermediates have very similar HOMO and LUMO energies and that their LUMO coefficients are very similar to each other so we cannot look to these features to explain the striking difference in the reactivity of these two species. The former (252) cannot be isolated when sulphonyl chlorides are treated with base instead the intermediate sulphene (e.g. 254) rapidly dimerizes.228 By contrast, sulphines (e.g. 255 and 256) are an easily isolated class of compound.226,229 The same... 

The oxidation of thiols is accelerated remarkably by traces of catalyst and this reaction forms the basis of petroleum sweetening processes. Although transition metal ions are the most effective catalysts, any additive capable of catalysing electron transfer accelerates the reaction. Nitrobenzene in dimethylformamide/potassium hydroxide [118], 2-nitro-thiophene, tetracyanoethylene, and 4-nitropyridine-N-oxide [118] are all good catalysts for the oxidation of 1-butane thiol. The alkaline hydrolysis of disulphides containing aryl, carbonyl, and alpha unsaturated groups also results in catalysis, apparently due to the setting up of a sulphinate—sulphenate redox cycle [119—121]. 

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